Hearts (心臓 Shinzō?) is the 1st chapter of the 2nd volume and the 5th chapter overall of the Attack on Titan: No Regrets manga, written by Gun Snark and illustrated by Hikaru Suruga.
Overview
The Survey Corps reach a resting point in the ruins of a building. Inside, the soldiers begin to set up camp for the night while Levi, Furlan and Isabel discuss their mission to steal important documents from Erwin Smith. The three conclude that Erwin has taken the documents outside of the Walls. While Furlan and Isabel go to search Erwin's belongings, Levi remains in the hallway on lookout. Levi reflects on how they got their mission from an unknown messenger sent by Nicholas Lovof, but he is interrupted by the appearance of Erwin himself. Isabel returns, and back in the entryway the trio consider killing Erwin to obtain the documents. Hange Zoë notices the three and interjects, introducing herself and asking for tips on vertical maneuvering equipment.
Summary
After finally making their way to a resting point, Isabel Magnolia and Furlan Church discuss the safety of staying within the ruins for the night. Regardless of what they think, Levi tells them to keep their guard up anyway.
The trio discuss their mission
Inside the soldiers begin unpacking crates and setting up places to sleep. Levi and Furlan discuss the ease of killing a Titan, with Levi stating they are faster than he originally thought. While he believes he can kill a regular Titan, he thinks abnormal Titans may be more of a problem, even for him. Their conversation quickly moves on to the documents they are looking for. Not having found them in Erwin Smith's room, Furlan believes that he is carrying them with him on the expedition, though Furlan wonders whether it is just a ploy by Erwin. Isabel adds that if Erwin was trying hard enough to hide something from the Survey Corps, Lovof would know. However, Levi questions if they can trust Lovof, to which Furlan replies that from Lovof's point of view they are just "worthless insects."
Levi sees Erwin while waiting for Furlan and Isabel
They quickly move on to their plan of finding the documents, with Furlan and Isabel searching Erwin's belongings. Levi is left to keep watch and distract Erwin and commander Keith Shadis, should they come back before Furlan can give the signal. While he waits, Levi thinks back to how they got their mission from a mysterious man sent by Nicholas Lovof. With the reward of money and a place in the capital, they were hard-pressed to pass up the opportunity without hearing the man out. Furlan convinces the man to give them more time to think about it, then quickly tells the others they will spy on him. He assumes only a noble or "big name" merchant could give them such an offer. He convinces them that once they have those documents they could blackmail Lovof themselves.
With Furlan's question ringing in his ears, he gets frustrated that Furlan and Isabel are not back yet. To his dismay, Erwin begins walking his way. The two make eye contact, and Levi quickly starts a conversation. The topic soon turns to Titans, with Erwin complementing Levi on killing an abnormal. But based on Levi's confession, he admits that there are still things they do not know about the outside world. Suddenly, Isabel comes back with an excuse ready; though Levi wonders why it is so bad.
Hange introduces herself
Back in the entryway, the three discuss killing Erwin to get the documents. Before they can finish, Hange Zoë appears wanting to talk to them. Believing they have been caught, Levi readies his knife to silence her. But to their surprise, she was talking about the Titan kill earlier in the day. She begins gushing about how excited she was and quickly introduces herself. She launches a flurry of questions at them, to which Furlan encourages Levi to be "sociable." It comes to their attention that everyone is watching them. Hange admits that it was inspiring to watch him kill that Titan and that it makes the others believe that humanity will not lose to the Titans. Isabel begins boasting about Levi's skills, which prompts Hange to offer her sweets. As Hange persists, Levi admits that he is self-taught and claims he is exhausted. Hange takes the hint and says farewell to them, offering to buy them lunch if they all make it back alive.
Though Furlan found Hange strange, he felt Levi could have been more helpful. Levi makes it clear, the only lives he wants to be responsible for are Isabel and Furlan's. Isabel admits she does not understand the "humanity taking back the world" stuff, but asks Levi if he feels it is okay for them to die for that sort of thing. As Levi stays silent, the day begins to fade away.